Four studies will investigate the use of monetary contracting and a behavioral program for helping adult men lose weight. Middle-aged men drawn from a sample of individuals found ineligible for the Multiple Risk Factor Intervention Trial at the University of Minnesota in 1973-75 will be contacted for participation in programs requiring monetary deposits which are returned contingent on successful weight reduction. Contracts will vary in size, in the conditions for refund (e.g. the time intervals and amounts of weight involved), and the amount of involvement of other people. The programs will be evaluated by assessing 1) participation rates, 2) weight loss and the maintenance of weight loss, and 3) adherence to behavior change recommendations. These studies will provide a significant test of both the individual efficacy and public health significance of weight contracting procedures.